1. Field of the Invention
This invention relates to a respiration filter made of a matrix-bonded filter medium, particularly of activated carbon and a method of producing such a filter.
2. Background Art
Such filters are known. Thus, U.S. Pat. No. 5,078,132 describes the manufacturing of a respirator in which the absorbent granules are combined with polymeric binder. This is done while pressing cylindrical and shell-shaped molded pieces. These molded pieces are then incorporated as filtration elements in a mask and are rigidly mounted to it.
A polymer-bonded granular adsorbent, absorbent, chemisorptive, or catalytic material and a method for producing molded pieces from it is known from DE 197 14 350 A1. A meltable polyethylene is intensely wetted with an oligocondensate in an appropriate mixing vessel, the fine-granular adsorbent, absorbent, chemisorptive, or catalytic material is added and the resulting mixture mixed intensely, then fed to a processing machine using a suitable conveying system and pressed into a molded piece inside a mold at temperatures in the range from 90° to 180° C., preferably 100° to 140° C., and pressures in the range of 0.0125 to 0.25 bar/cm2, preferably 0.0225 to 0.0625 bar/cm2, cooled in the mold and then removed from it. Using such molded pieces as filter elements for respiratory masks comprises a disadvantage in that their gastight fitting into inserts of respiratory masks or bonnets takes some process engineering effort. Furthermore, the mechanical stability of these molded pieces is limited along their edges.